Metallisation equipment protects wind turbines

Citation

(2007), "Metallisation equipment protects wind turbines", Anti-Corrosion Methods and Materials, Vol. 54 No. 5. https://doi.org/10.1108/acmm.2007.12854eab.003

Metallisation equipment protects wind turbines

Metallisation equipment protects wind turbines

Metallisation's Spanish Distributor, Descon Quimica, has recently supplied a metal spraying system (Figure 1) for wind turbine components to Granallados Molinero S.L. Molinero approached Descon because of its expertise in supplying automated metal spraying equipment and specific industry expertise in wind turbines. Molinero is new to the industry of thermal spraying wind turbine components and wanted to utilise the benefits of automating the process. This is in contrast to a lot of wind turbine thermal spraying which is carried out manually.

Figure 1 The Descon Quimica automated spraying system

The problem of atmospheric corrosion in wind turbines is significant, particularly considering that many turbines are placed in coastal or saltwater environments. It is for this reason that many manufacturers of wind turbines specify thermal sprayed Zinc or Zinc/aluminium alloys as a method of corrosion protection, to all or part of the steel wind turbine structure. Thermal sprayed coatings offer a very resilient finish, which is less susceptible to damage than many paint coatings. It is for this reason that the joint areas of the columns, and the components being assembled, are thermal sprayed to offer corrosion resistance in areas where paints may be damaged during assembly of these large items.

Descon Quimica has been supplying metal spraying equipment and materials for the protection of wind turbine parts throughout Spain, as well as other anti- corrosion and engineering applications, for many years. Descon provides anti corrosion protection for diverse industries including, liquid gas bottles, tube manufacturers, beer tanks, silos, parts of railroad bridges and aqueducts. This level of experience, combined with the global knowledge of Metallisation Ltd, made Descon Quimica and Metallisation the natural choice to supply Molinero with their automated spraying cell.

The spray equipment is being used by Molinero to spray components within the assembly that support the turbine blades. The actual coating with pure Zinc is only one part of the process. To ensure optimum adhesion of the coating, the surface of the turbine part is first grit blasted to a profile of around 75m and a cleanliness of SA3. A robot mounted arc spray system then applies an even 120m of Zinc at a spray rate of up to 36kg/h. A final coating of epoxy paint is then applied. This is an excellent way to protect wind turbines from corrosion and offers up to 20 years protection.

As a new user of metal spraying, Molinero is delighted with the support and service provided by Descon. The adaptability, flexibility and ease of use of the Metallisation Arc 140 equipment, has made the transition into metal spraying much easier for Molinero. One of the main reasons for selecting the Metallisation Arc 140 is that it is easily integrated with the robot cell, which then controls the spray gun to start and stop the spraying. The 20m push/pull supplies package also allows the energiser, wire and wire dispensing system to be located outside the dusty spray booth, giving the system greater reliability.

There are many advantages of automating the spraying process. Obviously, these generally apply when there are batches of identical parts to process, as is the case at Molinero. Automatic spraying will enable a very uniform coating thickness. Not only is this beneficial to the coating quality but also has a commercial value. Typically, if components are manually sprayed and the specification calls for a minimum coating thickness of 120m, it is very difficult to maintain a consistent coating depth. Even an experienced operator would usually coat to a minimum of 120m and in places, up to 180-200m or more. Through automation, an even 120m coating is achievable, offering on average, material savings in the region of 40 per cent. The spraying environment is also noisy and dusty. Through automation, the operator can remain outside the spray booth area.

Ignacio Sanchiz, Director of Descon Quimica, says: “We are really proud to have worked on this contract with Molinero. The demand for wind turbines across Spain and the rest of Europe means Molinero will have a vast market to supply metal spraying protection to. The ability of the Metallisation Arc 140 system to be so easily integrated with Molinero's robotic equipment, provides a perfect solution for all concerned.”

In the Arcspray process, the raw material, a pair of metal wires, is melted by an electric arc. The molten material is atomised by a cone of compressed air and propelled towards the work piece. This spray solidifies when it hits the surface of the work piece to form a dense coating, which protects against corrosion or reclaims/repairs components. Sprayed coatings may also be used to provide wear resistance, electrical and thermal conductivity, or for freestanding shapes.

Major advantages of the Arcspray process are that the coatings are available for almost immediate use, with no drying or curing times; there is no risk of damaging the component; the deposits possess a higher degree of bond strength than most other thermally sprayed deposits; the use of only compressed air and electricity mean more economic coatings.

For further information on surface coatings or the Metallisation equipment and processes, please contact Stuart Milton on +44 (0) 1384 252 464 or visit web site: www.metallisation.com